Method of producing cellulose and other products.



' the other hand those alkaline treatment.

BRUNO MARIA ERNST LORENZ POSSANNER, VOVN EHRENTHAL, 0E Cfi'lI-IEN,GERMANY,

ASSIGNGB OF FOETY-FIVE ONE-HUNDREDTHS TO MAX VON HAL-LE, 0F HAMBURG,

GERMANY. I

METHGD @lF PRQDUCING CELLULOSE AND OTHER PRODUCTS.

maaesa.

llo Drawing.

MARIA ERNsT many, have invented a new Method of Producing Cellulose andother Products, of whichthe following is the specification.

There are quite a series of vegetable fibers, which contain good fiberssuitable for making paper, which however on account of the chemicalconstruction are Very diificult to be opened out and which heretoforecould not be turned into bleachable cellulose in an economical manner.The reason of this is to be found in the chemical composition of thesefibers so diificult to be opened out differing from'the common rawcellulose material, such fibers containing usually larger amounts of lowcarbohydrates easily bydrogenized, moreover pectin substances andhemicelluloses and so on, composed when alkaline opening out 1s resortedto and result in yellow to dark brown products, that cannot be washedout from the fibers and cannot be bleached or at least extremelydifficult by the usual means. On

fibers, which are difficult to be opened out, will even withstand anacid opening out by the usual sulfite method because they are frequentlystrongly silicified and always contain an abundant amount of resin andgummy substances and also lignin substances, so that even by the aid ofthe acid boiling processes only a partial opening out is obtained whileat the same time cellulins are produced which cannot be bleached at allor with great difficulty. r

The object of the present invention is to overcome these diificultieswhich is done by submitting such fibrous substances difficult to beopened out to a combined acid and The fibrous substances are firstsubjected to the action of sulfite sulfite lye must be different fitesolutions contain about 1% Gail (MgO) said 'deserip liquor in one Thismethod diflers from the usual sulfite methods inasmuch as thecomposition of the The usual suland 45% with a proportion between thefree and the combined acid of about 2:1. When such fibrous substancesdifficult to be opened out are boiled with solutions of the EHRENTHAL,of.

which are all de- .such an extensive destruction of the usual pressureboilers,

substance is obtained,

Specification of Letters Patent. Patgntefl Sppt 14% 1915 Applicationfiled January 19, 1814. Serial No. 813,126.

which, it is true, is soft but which is brown and unbleachable onaccount of the fact, that in such fibrous substances a greater amount ofacid organic combinations of sulfurous acids (sulfon or sulfin acids)which are not fully combined by the small amounts of bases (lime,magnesium) and bring about the browning. To avoid this according to thepresent invention a solution is employed, which on account of a greaterpercentage 0 bases prevent the creation of such organic free acids. Theliquor is saturated with bases as much as possible without precipitatingmonosulfite which is difficult to dissolve, according to the percentagesay for instance 3 l% CaO at el5% S0 At a maximum pressure of about 56atmospheres and a maximum temperature of 125130 C. a boil- :ingof 6-7hours will be suflicient to open extent to make them tained bythesulfite boiling are to be worked in a known manner into sulfurous acidand on the other hand the organic substance dissolved therein, nothaving undergone on account of the weak boiling, will be recovered byneutralization and precipitation or by evaporation to a form fit for useor will be treated in a known manner for producing alcohol.

i The fibrous material gained by the sulfite boiling process which evenwhen washed,

'. still will have a more or less brown color and also contains numerousorganic combinations difiicult to bebleached is for the purpose of afurther opening out heated together with a 510% solution of calcine sodaor still better of caustic soda in open vessels (preferably in ableaching engine) to 8090 C. and then digested one or more hoursaccording to the condition of the fibrous materials. Thisis doneaccording to the counter current principle 50 that the mass not yetdigested with any alkaline liquor, so that t e liquor is saturated withorfresh soda solution comes into contact with v gamc substance as'muchas possible. In

no silicic acid, no ashes) the same manner the substance is hereafterwashed with cold or hot water according to the counter currentprinciple, the washing water saturated with alkali can be used also forthe alkaline digestion. By such alkaline treatment the organiccombinations that are diflicult to bleach are dissolved out from themass, so that the fibers thus purified can easily be bleached by theusual bleaching means. v

The organic substances contained in the alkaline solution consistsmainly of vegetable proteins, fatty matters as well as gum andresin-substances and can easily be eX- tracted by neutralizing theliquor with mineral acids in a powdery form while the dissolvedsilicates are not precipitated. For the purpose of neutralizationsulfuric acid or sulfurous acid will be most advantageous since by thesame the organic substances will be precipitated to the greatest extent.

lVhen the organic substance has settled the solution-of sulfate orsulfite of soda respectively will be poured ofi, and may be returnedinto the cycle of operation or after having been first rendered alkalinewith caustic lime. If sulfurous acid is used for neutralization thecalcium monosulfite which is formed by rendering the solution alkalineand which is .difficult to dissolve can also be returned into the cycleof operation for the preparation of thefresh sulfite solution.

The precipitated organic substance may according .to its chemicalcondition be used as an annual food when drained and dried (an analysisresulted in for instance with bagassc 5.25% protein, 3.30% f'attymatters, and can also be 7 sives.

1,15s,saa

usedfor producing glue and other adhe I claim: I 1. In the method ofproducing cellulose and other products, the step which comprises boilingthe fibrous material with a Weak acid sulfite liquor at a pressure of"from 56 atmospheres and a temperature not exceeding 125130 C., thenmechanically disintegrating and washing the sub stance, digesting itwith soda at increased temperature, and finally washing it out.

2. In the method 'of producing cellulose and other products, the stepwhich comprises boiling the fibrous material with a weak acid sulfiteliquor at a pressure of from. 5-6 atmospheres anda temperature notexceeding 125-130 (3., then mechanically disintegrating and washing thesubstance, digesting it with caustic soda at increased temperature andatmospheric pressure, and finally Washing it out.

3. In the method of producing cellulose, the step, which comprisesboiling fibrous material with a sulfite liquor Weak in acid andcontaining a base just short of'sufiicient to precipitate said base-asmonosulfite, said boiling being under apressure of from 5-6 atmospheresandat a temperature not exceeding ll C., then mechanically se'p aratingthe fibers and finally digesting them with soda at an elevatedtemperature and normal atmospheric pressure.

BRUNO MARIA ERNSTLORENZ POSSANNER VON EHRENTHAL.

